1. Field of the Invention
This invention relates to a micro device which has a thin film coil therein. As the micro device are exemplified a thin film magnetic head, a thin film inductor, a semiconductor device, a thin film actuator, or a composite device equipped with one or some of the thin film devices.
2. Related Art Statement
A thin film magnetic head including a writing element and a reading element is a type of micro device. Normally, the writing head includes a first and a second magnetic layers, a thin film coil, and a first and a second leading conductors. The magnetic layers are formed so as to be opposite to each other, and magnetically joined with a joint (back gap portion).
The thin film coil is formed so as to wind the joint in between the first and the second magnetic layers. The thin film coil includes a first and a second coil terminals. The first coil terminal is provided at the most inner side of the thin film coil and the second coil terminal is provided at the most outer side of the thin film coil.
One end of the first leading conductor is connected to the first coil terminal, and the one end of the second leading conductor is connected to the second coil terminal. The first and the second leading conductors are connected to pull-out electrodes (hereinafter, called as a xe2x80x9cbumpxe2x80x9d).
In order to develop the writing performance of the thin film magnetic head, it is required to increase the magnetomotive force, which can be performed by increasing coil current in the thin film coil or increasing the turn number of the thin film coil.
However, the increase of coil current causes the increase of the heat generation, so the writing performance of the thin film magnetic head is restricted because the heat generation must be reduced less than a given threshold value. Also, in view of the recent requirement of miniaturization for a micro device, it is difficult to increase the turn number of the thin film coil.
In addition, the increase of turn number of the thin film coil causes the elongation of the magnetic path by round pitches, resulting in the degradation of the high frequency performance of the thin film magnetic head.
It is an object of the present invention to provide a micro device of thin film layered structure, particularly a thin film magnetic head and a thin film inductor where a magnetomotive force can be enhanced without the increase of the turn number of the planer coil.
It is another object of the present invention to provide a micro device of thin film layered structure, particularly a thin film magnetic head and a thin film inductor where a magnetomotive force can be enhanced without the increase of the magnetic path and the degradation of the high frequency performance.
For achieving the above objects, this invention relates to a micro device comprising a first magnetic layer, a second magnetic layer and a thin film coil, wherein the first magnetic layer and the second magnetic layer are formed so as to be opposite to each other and magnetically connected via a joint, and the thin film coil includes a planer round portion winding around the joint in between the first and the second magnetic layers and a perpendicular round portion provided perpendicularly to the planer round portion.
According to the micro device of the present invention, since the perpendicular round portion is formed in the thin film coil, in addition to the normal planer round portion, a relatively large magnetomotive force can be generated without the increase of the turn number of the normal planer round portion in the thin film coil, originated from the perpendicular round portion. As a result, the magnetomotive force can be enhanced without the substantial increase of the magnetic path and thus, the reduction of the high frequency performance.
For example, the above-mentioned perpendicular round portion can be formed as follows. A first leading conductor and a second leading conductor are additionally prepared. Then, the thin film coil is formed so as to include a first coil terminal provided at the most inner side thereof and a second coil terminal provided at the most outer side thereof. Then, the second leading conductor is connected to one end of the second coil terminal. One end of the first leading conductor is connected to one end of the first coil terminal passing below the second magnetic layer, and the other end of the first leading conductor is pulled out in an opposite direction to the first coil terminal above the second magnetic layer.
In this case, the perpendicular round portion by about half to one turn is composed of the first leading conductor and the first coil terminal.
A given coil current is supplied to the thin film coil through the first and the second leading conductors.
The first leading conductor may include plural conductive parts. In this case, one end of one of the conductive parts is connected to one end of the first coil terminal passing below the second magnetic layer, and the other end of the one of the conductive parts is pulled out in an opposite direction to the first coil terminal above the second magnetic layer. Then, the conductive parts are electrically connected to one another at their respective ends. Therefore, the turn number of the perpendicular round portion can be increased, so that a larger magnetomotive force can be generated.
In another embodiment, one end of the second leading conductor is connected to one end of the second coil terminal passing below the second magnetic layer, and the other end of the second leading conductor is pulled out in an opposite direction to the second coil terminal above the second magnetic layer. In this case, the perpendicular round portion by about half to one turn is composed of the second leading conductor and the second coil terminal.
The second leading conductor may include plural conductive parts. In this case, one end of one of the conductive parts is connected to one end of the second coil terminal passing below the second magnetic layer, and the other end of the one of the conductive parts is pulled out in an opposite direction to the second coil terminal above the second magnetic layer. Then, the conductive parts are electrically connected to one another at their respective ends. Therefore, the turn number of the perpendicular round portion can be increased, so that a larger magnetomotive force can be generated.
In the present invention, the above-mentioned two types of perpendicular round portions may be combined. That is, one perpendicular round portion is formed of the first leading conductor and the first coil terminal, and another perpendicular round portion is formed of the second leading conductor and the second coil terminal.
As the micro device are exemplified a thin film magnetic head, a thin film inductor, a semiconductor device, a thin film actuator or a composite device with one or some of the devices. Particularly, the micro device can be preferably for the thin film magnetic head or the thin film inductor.
The thin film magnetic head includes a micro device as mentioned above and a slider. The micro device is supported by the slider.
This invention also relates to a thin film magnetic head device which is characterized by comprising a thin film magnetic head as mentioned above and a head supporting device to support the thin film magnetic head.
Moreover, this invention relates to a magnetic recording/reproducing device which is characterized by comprising a thin film magnetic head device as mentioned above and a magnetic recording medium for writing and reading commensurate with the thin film magnetic head.
Other objects, configurations and advantages will be described in detail hereinafter, with reference to the accompanying drawing. It is to be understood that the invention is not intended to be limited to the following specific embodiments.